Field of Invention
The present invention relates to the underground pipeline repair technology, and more particularly to a polymer grouting method for processing leakage and sand inrush caused by the pipeline section displacement of the underground pipeline under complicated geological conditions including soft soil layer, quicksand and the underground river.
Description of Related Arts
The underground pipeline network is an important part of urban infrastructure, is the material basis and the indispensable lifeline for the survival and development of the city. In recent years, with the strengthening of safety awareness and environmental awareness, the safety of the underground pipeline is paid more and more attention.
The underground pipelines belong to hidden works, due to Chinese complex geological conditions, the underground pipelines often encounter mud, soft soil, underground river, sand, and other special geological environment in the building process, if not handled properly, after building the underground pipeline, the pipeline section joint is prone to displace, which results in leakage and sand inrush, if the situation is not serious, the pipeline is blocked and the function thereof is affected, if the situation is serious, the ground surface may be subsided, the traffic is congested, people are damaged, and the security of nearby buildings is threatened. Every year, the direct and indirect economic losses are up to several billion dollars due to leakage and sand inrush of the pipeline.
Existing underground repairing methods are mainly two kinds: one is excavation repairing and pipeline renewing, the other is non-excavation method. The excavation repairing method is excavating the soil layer above the damaged pipeline, partially repairing the damaged pipeline or integrally changing the new pipeline. In spite that the method is capable of effectively solving the pipeline settlement, it has high construction cost and long time limit to a project, residents and traffic in the construction area was severely disrupted. Furthermore, in many cases, dense urban underground infrastructure, ground green area and buildings and busy traffic leave little room for the excavation, so that it is not able to achieve the repair and change of the underground pipeline. The non-excavation method currently includes the cured-in-place-pipe method, the interspersed method, the pipe bursting method, the folding lining method and spraying method. In the cured-in-place-pipe method, one end of the soft pipe impregnated with resin is turned and fixed at an entrance of the pipeline to be repaired, and then an inner layer of the soft pipe impregnated with resin is turned to an external by hydraulic pressure or air pressure and is closely attached to an inner wall of an old pipeline, and then the resin is solidified to form a layer of rigid lining with anticorrosive anti-seepage function which is closely attaching to the inner wall of the old pipeline. Its shortcomings are that the special construction equipment is needed, and it is required for workers to have higher technical level and experience. In the interspersed method, a new pipeline is directly dragged into an old pipeline, and the grouting is performed in an annular gap between the old pipeline and the new pipeline. Its shortcomings are that the flow area of the original pipeline is largely reduced, and the grouting is needed after completing construction. In the pipe bursting method, the front-end steel conical head shatters the old pipeline under the action of the pneumatic hammer or tractor, the lining plastic pipeline goes forward followed by the conical head, and finally the construction of replacing the old pipeline is completed. Its shortcomings are that the excavation of the ground needs to be directly connected, for serious displacement of the original pipeline, the new pipeline may be seriously displaced, and the starting working pit and the receiving working pit are needed to be excavated. In the folding lining method, the pipeline is made of PE or PVC, the geometrical shape of the pipeline is changed to reduce the fracture surface thereof in the factory or the construction site before construction, and then the pipeline with reduced fracture surface is dragged into the original pipeline, when the pipeline is in place, by heating or pressing, the folded pipeline expands and restores the original size and shape, so as to form the lining pipe which is closely attached to the original pipeline. Its shortcoming is there may be structural damage (broken or trend derivation) in construction. In the spraying method, a layer of film is sprayed to an interior of the pipeline by cement mortar or organic chemical pulp for repairing the old pipeline. Its shortcomings are that high requirements for pipeline cleaning and blocking are needed, longer repairing time, limited ability to repair pipeline defects, time and energy waste and instable quality. In spite that these methods are able to solve the structure deficiency and water leakage of the underground pipeline, most of them need to empty the water accumulated in the pipeline and then the construction is operated. If the quick sand and other complex geological conditions exist outside the leakage position of the pipeline, the quick sand continuously enters into the pipeline while pumping, which results in the pumping area of the quick sand, if seriously, even leads to the ground subsidence. Therefore, it is urgent to develop a new method for blocking leaking and sand inrush of an underground pipeline under complex geological conditions.
The polymer grouting technology is the foundation rapid reinforcement technology developed in 1970s. In the technology, the non-aqueous reaction type two-component polymer material is injected into the foundation, two materials rapidly reacting, expanding and solidifying after mixing to reinforce the foundation, filling the pumping area or promoting the floor. The polymer material has light quality, fast response, good durability, and excellent anti-seepage performance. Currently, the polymer grouting technology is mainly applied to roads, tunnels, dams and other large infrastructure seepage, consolidation and restoration projects. The present invention aims at the deficiencies of the underground pipeline repairing technology under complex geological conditions in China, and combines the polymer film bag grouting technology, the polymer pipe grouting technology with the polymer geotextile bag grouting technology to develop a polymer composite grouting method for blocking leaking and sand inrush of an underground pipeline. China has no relevant reports.